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By Bruce D. Hansen

For many years, Newmont has focused on improving its operations. After the merger between Newmont and Santa Fe Pacific Gold, Newmont created synergies of more than $50 million a year in Nevada. This was done primarily through optimal ore movements and consolidation of various functions. During the current period of low gold and copper prices, Newmont has refocused its efforts on efficient operations worldwide. At its mine facilities in Nevada, Newmont has used a combination of several strategies to decrease the costs of operations and to increase profitability. These include computer technology, optimal use of infrastructures, procurement strategies, functional consolidation, enhanced mine planning and several available metallurgical processing options.

Jan 1, 1999

By M. Ahrens

The paper describes the main drive systems of an iron ore pelletizing plant and related important design aspects. It is shown how today?s drive systems provide the desired flexibility for the process and lead to high energy efficiency and system reliability. With respect to electric drives expansion projects have many technical issues in common with green-field installations. However, there are aspects where important, distinct differences occur. It is shown which considerations for selecting and sizing drive systems for such a plant as well as for integrating them into an overall plant control concept need to be taken into account. Besides the design of the drive systems a key aspect for such an expansion project is the network interaction. Harmonics levels at different points in the plant network need to be checked carefully with simulations during the design phase to avoid problems later-on during operation. The power factor compensation and the harmonic filtering of the new production line cannot be designed independently of the already existing plant. The paper highlights areas where problems could occur and which points need to be paid attention to when a plant is expanded.

Jan 1, 2008

By J. A. M. Cano

Pot Grate tests were carried out in the pilot plant at Samarco producing pellets containing SiO2 between 2.0% and 2.2% in a wide range of basicity to be used in blast furnace. These pellets were submitted to tests in Samarco's laboratory and another laboratory in Germany to evaluate the metallurgical properties. The pellets in the binary basicity range (CaO/SiO2) from 0,87 to 0,95 were those that presented the best results in the Pot Grate tests. Based on the results, these pellets are being routinely produced?on industrial-scale confirming the results observed in laboratory tests.?

Jan 1, 1994

By O. Kangal

Flame retardant materials can be incorporated or applied to products, including plastics and textiles, to increase their resistance to fire. Incorporating a flame retardant in combustible materials and plastics is a common procedure to reduce the risk of fires. Flame retardant applications include interior and exterior woods, structural steel columns, fabrics, open and closed cell foam, pressure treated wood, Formica and all types of fabrics for use in commercial applications as well as residential applications where their fire protection products can save lives and valuables. Huntite and hydromagnesite are amongst the most important flame retardant additives materials. Although various areas of the world have potential huntite and hydromagnesite deposits, their place in industry is not well known, and a detailed field search for their deposits has not yet been conducted. They are active during the starting phase of a fire, in that they prevent the spread of an inner or exterior source of ignition to the flame-retarded material, thereby, preventing, delaying or inhibiting the spread of a fire. Flame-retardants are, therefore, just one element among many in a concept for preventive fire safety. To obtain huntite and hydromagnesite concentrates that are more than 95% pure, which are used in flame retardant industry, flotation tests were conducted on low-quality huntite and hydromagnesite ores.

Jan 1, 2009

By Richard L. Bullock

Believe it or not, mine evaluation and feasibility studies are as old as the industry itself. In the first recorded writing on mining by Agricola (1556), he gave several clues as what to look for in evaluating a mine, to determine if it was economically feasible. Below is the guidance from Agricola, with my interpretation of what he would include today. Now a miner, before he begins to mine the orebodies must consider seven things, namely: ? The situation (the geography/topography). ? The conditions (the geologic/mineralogic and mining conditions). ? The water (availability, hydrology and ownership). ? The roads (plus the railroads, power lines, all other infrastructure). ? The climate (the weather-rainfall/environment). ? The right of ownership (the land and legal entitlement). ? The neighbors (the social environmental concerns of the area). It is amazing how much of his guidance has not changed in 455 years. Yet Agricola gives no guidance on determining the correct cost, or determining the correct commodity pricing. But he does give a few words of caution on the related ethics involved on buying mineral properties: ?A prudent owner, before he buys shares, ought to go to the mine and carefully examine the nature of the vein, for it is very important that he should be on his guard lest fraudulent sellers of shares should deceive him.? Three hundred years later (1866), to further amplify this point, in the most famous thing that Mark Twain never said, as an introduction to a lecturer to an audience of gold-miners at Red Dog, CA, the famed author/humorist allegedly described a mine as ?a hole in the ground owned by a liar? (Farrar & Rinehart, 1935). So, one might conclude that between these two dates, the mining industry did little to improve its reputation. Unfortunately, since Mark Twain allegedly made those remarks, we have not done near enough to gain accountability for the mineral industry.

Jan 1, 2011

By G. Bee, Z. Gavelan, R. Espinel, Y. Roditis, X. Ochoa

In August 1996 Barrick Gold Corporation acquired the Pierina property, an advanced stage exploration project, high in the Andean Cordillera of Peru and in November 1998, in a record time of just over two years, poured the first gold. After more than three years of a very successful operation at some of the lowest operating costs in the world, this presentation serves to briefly describe the project through design, construction and start-up and in particular to spotlight some of the challenges that have been overcome in valley heap leaching in a high rainfall, alpine setting.

Jan 1, 2002

By Timothy J. Orr, Robin J. Burgess-Limerick, Jennica L. Bellanca, MARGARET E. RYAN

Powered haulage continues to be a large safety concern for the mining industry, accounting for approximately 50%of the mining fatal accidents every year. Among these fatal accidents, haul-truck-related accidents are the most common, with 6 of 28 and 6 of 27 fatal accidents occurring in 2017 and 2018, respectively. To better understand why these accidents continue to occur and what can be done to prevent them, researchers reviewed the 91 haul-truck-related fatal accidents that occurred in the USA from 2005 to 2018 and performed bow-tie analyses using the final reports published by the Mine Safety and Health Administration. The analyses explore the context of the accidents with a focus on the initiating event, event outcome, hazards present, and possible preventative and mitigative controls. Overall, the vast majority of the accidents resulted in a haul truck colliding with the environment, and the majority of these events were initiated by loss of situational awareness or loss of control. The majority of the hazards were related to design and organizational controls. The results of this study suggest a need to investigate operator decision-making and organizational controls and to focus on improving design and operation controls such as mine design and operational procedures.

Feb 22, 2021

By A. Johnson

When are SMART transmitters the smartest choice? To answer this question requires a closer look at SMART transmitter technology. It is necessary to understand this technology in order to recognize how it can best be utilized to give the greatest value for the application. And, once the decision to buy transmitters has been made, it becomes a question of whose SMART transmitter to buy. For, although the under-lying technology is similar, the differences that exist in how the technology has been implemented can make a dramatic difference in the end result. What prudent users of SMART technology do is to analyze their needs by application before making their buying decision.

Jan 1, 1988

By Ashis Bhattacherjee, Rahul Upadhyay, Nearkasen Chau, Aditya Kumar Patra, Dhanjee Kumar Chaudhary

Heavy earth-moving machineries used in open-pit mines intensively expose the drill operators to whole-body vibration and shocks and thus to musculoskeletal disorders. The roles of an individual, machine, and rock-related factors in their exposure remain poorly understood. This cross-sectional study investigated their role among 39 drill operators from Indian iron ore mines. It shows that 70% of the operators were exposed to high levels of vibration, above the limit values recommended by ISO 2631-1. Multiple linear regression models showed that the whole-body vibration and shock exposures were strongly associated with operator’s age, drill machine model, rock’s hardness, uniaxial compressive strength, and density. The role of body mass index was close to significance (p = 0.08). Univariate analyses found that drill’s age, seat pad thickness, and seat backrest height were also strong predictors. These results help in identifying risky operators, materials and occupational situations, and in implementing appropriate prevention and intervention to reduce and monitor the exposures and health risk.

By R. J. Pruett

The Georgia kaolin district is the world’s largest producer of kaolin. Georgia production tripled from 2.87 Mt (3.17 million st) in 1968 to8.35 Mt (9.2 million st) in 1998. Development of the Georgia kaolin industry can be traced to the identification of the mineral resource, the adoption of innovative process technologies and the creation of markets for kaolin. Georgia kaolin is an abundant and high-quality resource that shows a range of advantageous properties. Technical developments in wet processing, delamination and calcination allowed production of high-value products. The use of kaolin pigments in the paper industry provided a market that absorbed the rapid growth in kaolin production.

Jan 1, 2000

By Rex E. Loesby

The marble deposits of Yule Creek were first discovered in the late1870s. Minor quarrying occurred between that discovery and the early 1900s. Major development occurred in 1905, when Channing Meek, with some help from the Rockefellers, raised $3 million to develop the Colorado Yule Marble Quarry. That is $50 million in today’s dollars. Some of the words used to describe the marble deposit were “gigantic, remarkable, flawless and immense.” Boosters proclaimed, “The marble age is here.” Obviously, dreams were big for Marble.

Jan 1, 2003

By D. Newman

Multiple seam mining is prevalent in Southern Appalachia because economically mineable coal seams are numerous and frequently occur in close vertical proximity. West Virginia, Kentucky, and Virginia have 117, 55, and 40 mineable coal seams respectively. It is extremely rare to have an underground mine that has not been undermined, overmined, or has mining adjacent to it. In many cases the multiple seam mining is concurrent with extraction sequenced in superjacent seams. Because underground mining is focused on recovering the most valuable reserves, mining is rarely practiced from the top seam down, which is the practice most conducive to stability. The combination of room-and-pillar mining methods that include development only, small block, partial retreat, full retreat, and longwall mining produce a wide range of mining geometries and complexity in underlying and overlying seams. In the future, the number of multiple seam operations will increase as reserves are depleted and future mines are, by default, located closer to abandoned mine workings. The improved coal market has transformed many formerally uneconomically mineable seams into attractive reserves. The approaches and methodologies used for multiple seam stability analysis are dictated by the site conditions, including overburden/interburden thickness and lithology, mining geometry, and the mining methods in both the active and abandoned mines. Multiple seam stability analysis using analytical and numerical methods is illustrated by two case histories that reflect close proximity room-and-pillar mining and mining in bump prone situations.

Jan 1, 2007

By Timothy P. Smirnoff

Sustaining the region?s mobility needs, achieving projected economic growth, and maintain Midtown Manhattan as a center of regional, national and global importance has led to continued investment in commuter rail and transit infrastructure in New York City and resulted in design and construction of large underground caverns. The current plans for stations in Manhattan include New York Penn Station Expansion (NYPSE) caverns for Trans Hudson Express (THE) Tunnel Project for New Jersey Transit (NJ Transit) and the Port Authority of New York and New Jersey (PANYNJ), Metropolitan Transportation Authority Capital Construction Long Island Railroad (MTACC/LIRR) twin caverns for East Side Access (ESA) Project, and station caverns of the No. 7 Line Subway Extension Project and Second Avenue Subway Project for Metropolitan Transportation Authority Capital Construction/New York City Transit (MTACC/NYCT). This paper provides a general overview of these large caverns now in design or construction in Manhattan, the area?s geologic setting, the geotechnical factors considered and approaches commonly applied for cavern design.

By L. K. Marshall

Last month's engineering fundamentals article discussed some general considerations of underground mine ventilation. This month's article takes a look at auxiliary ventilation-brattice, fans, and ducting-in underground mines. The need for good, efficient auxiliary ventilation increases as mines get deeper and move farther from ventilation shafts. New mining methods and equipment resulted in faster work area advances, liberating more dust, gas, and heat. As a result, worker health and safety requirements in the face area have become more stringent. For all these reasons the safety and efficiency of any underground mine depends heavily on its auxiliary ventilation. The purpose of such ventilation is to supply sufficient quantities of clean air to the face of the drift and to maintain air quality within desired limits until expelled from the mine.

Jan 2, 1982

By N. A. Abdel-Khalek

The amenability of carbonate separation from a sedimentary phosphate ore using a bioflotation process was studied. Two types of bacteria were chosen for this study. The experiments were performed using oleic acid as collector. The flotation experiments were carried out using statistical designs for optimizing the main operating parameters. A concentrate containing 0.78% MgO and 30.15% P2O5 with a recovery of 92.31% was obtained from a feed containing about 2.45% MgO and 27% P2O5. These specifications could not be obtained using conventional flotation experiments under similar conditions in the absence of bacteria. Measurements of zeta potential, adsorption of bacteria and collector, as well as froth power, were performed to explain the role of microorganisms in the surface modification of both dolomite and phosphate and in their interaction with the collector.

Jan 1, 2009

Introduction The US mineral industry in 1983 participated in the recovery from the recent recession. Compared with 1982, the value of raw nonfuel mineral output rose 8% to $21.2 billion. The $218 billion worth of goods processed from this crude mineral output represented a 9% increase over 1982. Even in real terms, these figures reflect growth. Demand for nonfuel mineral materials, of course, depends on the overall state of the economy, which steadily improved each quarter in 1983. Of particular importance to the mineral industry were surges in key mineral-consuming sectors such as construction and automobile manufacturing. New housing starts rose one-third, to 1.7 million units, while automakers turned out about 35% more cars (6.8 million) and 25% more trucks (2.4 million) than in 1982. These are significant increases, even considering recent trends toward smaller, lighter vehicles, and multiple-unit housing. A comeback for the mineral industry, however, is bound to proceed unevenly, particularly at the beginning. Traditionally, the industry lags behind the rest of the economy during a recovery, and some mineral products respond to overall economic improvement more quickly than others. This pattern has been repeated many times and the industry is used to it. Mineral executives know it is best to be patient and cautious during the first stages of an economic upturn. Many experts say that it may take extraordinary toughness, patience, and caution this time around. Steel Improves Raw steel production - a major indicator of both material use and mineral production - rose 14% to 77 Mt (85 million st), stimulating a 7% rise in domestic iron ore production to 39 Mt (38 million It). Still, the iron ore industry operated at less than half capacity, with most major mines remaining closed for part of the year. Iron ore imports dropped 24% to 10 Mt (11 million st), so demand was partly met by withdrawals from stocks. Despite the increase in steel production for 1983, output remained far below levels of just a few years ago. For example, 1983 production was still 29% less than in 1981. Raw steelmaking capacity actually declined about 10% during the year to 122 Mt (135 million st). The industry continued to cite steel imports, especially those from developing nations, as a major cause of domestic capacity loss. As long as steel production remains weak, steelmaking metals suffer. Domestic producers of bulk ferroalloys of chromium, manganese, and silicon operated at about one-third capacity in 1983, with six of the 19 companies involved being closed all year. The US mined no manganese or chromium, and very little nickel, although the country's only nickel mine did resume production in November. Molybdenum production, at 13.6 t (15 st), was only about one-third as much as in 1982. The major molybdenum mines, Climax and Henderson in Colorado, remained closed all year. To meet demand, molybdenum stocks were halved to 19 t (21 st). Mine shipments of tungsten, another mineral tied to steel production, dropped 30% to 1.1 kt (1,200 st) of contained metal. One of the most positive responses to the general economic recovery came from the aluminum smelting industry. By the end of the year, it was operating at about 79% capacity, compared to 59% in January. Nevertheless, the 3.3 Mt (3.64 million st) of primary aluminum produced represented only a slight increase over 1982. Total bauxite imports were about 27% below 1982 levels. Production of magnesium metal rose 11% to 100 kt (110,000 st). But titanium was more typical of other

Jan 5, 1984

By J. W. Devon

The coal mining industry is divided into two distinct economic segments based on Coal Supply Agreements. Coal supply agreements generally fall into two categories, spot or long-term, with the selected contract term being driven by the buyer's market expectations, security of supply considerations, fuel tonnage and quality requirements, and economics. Short-term or spot coal purchases are generally market driven and are highly competitive in today's marketplace. Long-term contracts, particularly those involving captive mines and mine-mouth power plants, are commonly driven by considerations other than economics. These other considerations, such as Reserve Conservation and Resource Recovery, Security of Supply, and Maintenance of Levelized Costs may increase the cost of coal, often needlessly and without benefit to the buyer or seller. The basic economic principles which guide the market driven metals industry and generally guide the spot coal sector of the coal industry should apply equally well to the long-term coal supply contract. The artificial constraints imposed as a result of regulated rates of return should be re-examined and in most cases, abandoned. There are many methods of surface and underground coal mining being used today such as, open-pit, contour, mountaintop, and area mining for surface mineable reserves; conventional, standard continuous and super-section continuous miners, and longwalls for deep reserves; and highwall miners, thin seam miners and augers in between. This discussion is primarily directed to surface mining, however the same principles of least cost mining on a Net Present Value basis must be considered in all cases.

Jan 1, 1994

By Dell H. Adams

Coal exploration may be defined as the acquisition of data necessary to define and acquire a block of coal which can be mined at a profit. Unlike ore minerals, coal resources are widespread and relatively abundant with supply exceeding demand in almost every case. Thus simple discovery of coal is generally not enough. The chemical and physical variability of individual coal seams, the capital intensive nature of coal mine development, and the changing patterns of utilization require that a multiphase, three-dimensional evaluation be made of each potential reserve. Factors which must be investigated include not only the quantity and quality of the coal but also the geologic, hydrologic, and engineering characteristics of the seam and its surrounding strata. Acquisition of property to provide a secure base for exploration and mine development is equal in importance to the geologic and engineering programs. The successful development of a coal reserve requires that control of coal and, in the case of a strip mine, the surface be in the form of contiguous blocks of sufficient size to support mining.

Jan 1, 1981

By Smart Chika Obiora, Anthony Chukwu

Mining and processing of raw materials is one of the earliest activities of man for survival and development. The products are used for making jewelleries, metal tools, and for exchange of goods and services. However, despite the benefits of mine recoveries, it’s negative and long term effects on the environment and lives remain the point of discussion throughout the world. This study summarizes findings of researches in active/abandoned lead–zinc mines in Enyigba and Ishiagu mining districts including social surveys in the localities surrounding the mines in order to ascertain the effects on the inhabitants. Lead–zinc mining in Enyigba and Ishiagu, southeastern Nigeria has lasted for decades and has affected the socio-economic well-being of the host communities. There are evidences of soil, water, and plants contamination by Pb, Zn, Cd, and Mn in these mining communities. The mining activities also affect the overall social development of the host communities. These effects include retardation in educational development, health care provision, unemployment, and access to potable water supply. Others are rise in poverty level, social amenities, sanitary/hygiene level, high cost of living, and fertility rate. Possible mitigation strategies such as to liaising with relevant government agencies in collaboration with mine owner, mine workers, and host communities can ameliorate these negative effects and promote environmental sustainability.

Feb 24, 2023

By D. Loring, J. Almgren

Climax Molybdenum Company’s Henderson Mine is a large panel caving molybdenum mine located about 43 miles west of Denver, Colorado. Three Joy M120-72-880 fans are installed in parallel on the No. 1 exhaust shaft. Throughout the mine’s history, ventilation changes such as the completion of the No. 5 exhaust shaft have decreased the utilization of these fans. To optimize fan performance they have been run with the full complement of 16 blades, down to as few as four blades. Since the completion of ventilation upgrades associated with the Henderson 2000 project, one surface fan has been operated under normal conditions with 10 or 12 blades. With the completion of a new network model of the Henderson ventilation system, a tool was built to develop fan curves for possible future fan configurations and predict future fan performance. This paper describes the tool and its use at Henderson.

Jan 1, 2007